Statfs p atp n t off



A. LUNN STOVE PIPE March 27, 1934.

Filed Oct. 18, 1930 INVENTOR Alvin Lun n ATTO EY Patented Mar. 27, 1934 P AT ' STOVE PIPE Alvin Lunn, Portland, reg., assignor to Northwestern Metalware 00., Portland, 0reg., a cor-' notation of Minnesota Application October 18, 1930, Serial No. 489,572

1 Claim.

My invention relates to so-called self-locking stove pipe and has for its particular object the provision of means for making a separable joint for stove pipes which is capable of being set up gin minimum time and with the minimum expenditure of eiiort.

A further object of my invention is to provide a joint of this character, which is economical to manufacture and which is capable of sustaining substantial distortion Withoutpermitting 'the parts of the same to be disconnected.

The details of construction and mode of assembly of such a type of stove pipe are hereinafter described in greater detail and with reference to the accompanying drawing, in which:

Fig. 1 is a View of one length of stove'pipe before the same is locked;

Fig. 2 is a view of the separable lock or key for such pipe; and Fig. 3 is a view of such length of pipe with the key in place.

My invention is particularly adapted to be used with stove'pipe, although obviously it can be used with any type of pipe or the like, in which the same necessity for making a seam exists.

A length of stove pipe made up in accordance with my invention comprises a section of pipe a and a separable key 1). Such pipe is provided with a circumferential shoulder c, as is common, which shoulder is located adjacent one end length of pipe. Such length of pipe is crimped, as at d, to decrease the over-all circumference of the pipe at such point. Such lengths of pipe are thus adapted to be made into an overlapping conduit, in which the orimped end is inserted into the uncrimped end of the adjacent length. Extending longitudinally of such length of pipe are two inturned flanges e, which are bent back upon the remainder of the pipe, but spaced therefrom. The pipe adjacent such flanges, as at f, is ofiset so that the inturned portion or flange is in substantial alinement with the remainder of the pipe and the offset portion f extends outwardly therefrom. This is for the reason that the pipe before assembly, as is shown in Fig. 1, is in shipping condition and it is adapted to be nested around or within a number of other lengths of similar type, so that the bulk is out down. In other words, it is impractical to ship lengths of stove pipe in assembled condition, for the reason that they are too bulky and thus such lengths are completely formed but the longitudinal seams are not connected, so that a number of lengths of pipe can be arranged in nested or 5s overlapping condition.

When shipping pipe in this manner, the bentover portions forming, the seam are easily deformed, so that thereafter the seam can be joined only with great difliculty. In standard pipe, that is pipe now generally sold on the market, it is common practice to arrange the edges of the pipe adjacent the seam into one inturned flange and into one out-turned flange. The out turned flange is capable of being distorted easily by a blow struck upon the outside of the pipe and the flange on the inside by compression of the entire package. It is with the purpose in mind of minimizing the possible injury of the pipe adjacent the seam in this manner that the portions at each side of the seam, which are formed into reversely-arranged bends, are offset as has been described heretofore. The reversely-arranged ends, thus are protected and receive no blow to which" such pipe might be subjected and. such intermediate portions are much stronger and thus less liable to be distorted.

The removable key I) is preferably made of heavier gauge material than the section of pipe, not only to stiffen the same and prevent the parts becoming disengaged, but also for the 7 reason that if such inturned flanges might be distorted that such key is sufficiently stiff to serve as a wedge to force such sections into alinement, rather than to distort the key similarly.

The key is formed of a single piece of material, in which the lateraledges b are bent back upon the body but spaced therefrom a substantial distance, slightly in excess of the thickness of the material making up the section of pipe. One end of the key is formed with the lateral edges out upon an inclined taper, thus forming guiding surfaces to aid in the insertion of such key in place on the seam.

The flanges e formed upon the section of pipe either extend in a lineal direction, or upon a smooth curve. The key is made of flexible but relatively elastic material and is either formed so as not to'extend parallel to the flanges of the pipe, or is flexible so as'to be susceptible of being thus formed immediately prior to assembly. This permits the key I) to be forced in place only under the application of substantial force and the key being heavier and stifl'er thus similarly deforms the flanges of the section of pipe and rendersthe removal of such key difiicult, so as to tend to prevent the inadvertent disengagement or" such key by lateral shifting.

By making the seam portion ofiset with respect to the general curvature of the pipe to such a degree that the flange portions are substantially in alinement with the general curvature of the pipe, a tight fitting joint is secured between the marginal portions of the key and the faces of the offset portions which supplement the seal provided by the interlock of the opposed flanges of the pipe and of the key b.

I claim:

A section of stovepipe provided with a longitudinal, separable seam, the edges of the pipev defining said seam comprising inturned lateral flanges bent over and spaced from the adjacent portions of said stovepipe a distance slightly in excess of the thickness of said stove- 

